Hello, I am troubleshooting an issue for a person that is getting an NDR when sending appointments but not emails, and I have tried the steps outlined here: http://support.microsoft.com/default.aspx?scid=kb;en-us;312433 When looking around, I noticed there is a person with the same name and UserID, but each are in a different domain in the forest. However, I also noticed that their Exchange mailbox alias (not email addresses) are the same (but a different mix of upper and lower case objects.) There are in different administrative groups as one is on a 2003 server and the other on a 2007 box.) I was wondering if this could cause problems. Is the scope of an Exchange alias the organization, the administrative group, or server? Thanks!

Hi, I think its organization wide: If your exchange 2007 mailbox has alias "Alias1" and primarySmtpAddress user@domain.com then what is the result of this command in EMS: set-mailbox user@domain.com -Alias "Alias1" does it give error? Regards,Laeeq Qazi|Team Lead(Exchange + Sharepoint + BES + DynamicsCRM) www.HostingController.com

The alias could be numbers or letters and your problem would still occur.